The problem of spam is well-recognized in established communication technologies, such as electronic mail. Spam may include unsolicited messages sent by a computer over a network to a large number of recipients. Spam includes unsolicited commercial messages, but spam has come to be understood more broadly to additionally include unsolicited messages sent to a large number of recipients, and/or to a targeted user or targeted domain, for malicious, disruptive, or abusive purposes, regardless of commercial content. For example, a spammer might send messages in bulk to a particular user to harass, or otherwise, disrupt their computing resources.
However, a sender of a large number of messages might not be considered a spammer. For example, an educational, financial institution, health institution, or the like, might send a large number of messages to its alumni, members, or the like. Similarly, known and/or generally acceptable merchants might send large number of messages that some recipients may actually want to receive. Such bulk message distributors may be well known by some of its recipients, who may actually seek to receive the messages. Thus, a sender of a large number of messages cannot be classified based solely upon the quantity of messages it sends. However, in other situations, even messages from well known merchants might be considered as junk mail, or spam, by other recipients. Because some recipients of the bulk messages may know and accept messages from these senders, while other recipients would consider such messages as spam, filters often need to be individually tuned to allow the messages to be delivered for each individual. Thus, while some generic spam filters may work for many messages, they may not work for a given individual.